The present disclosure is directed to an aluminum based abradable material which includes hard phases to help wear any material transfer back off the tips of a rotating part, such as a compressor blade, and stationary parts such as cantilevered vanes.
Compressor efficiency is related to blade tip clearance, outer air seal roughness, and gas permeability. Coatings for the low compressor, against which compressors blades seal and rub, are typically aluminum based and applied to the casing surrounding the blades. Under certain conditions, the coatings transfer metal to the tips of the airfoils. This transfer is often localized on the airfoil tip, forming a bump on the airfoil tip and concurrently causes localized wear of the seal in what is known as a record groove pattern. The result is increased average tip clearance and increased roughness in the air flow direction.